gnutls_session_get_desc: avoid printing a NULL valuetmp-fix-desc

When gnutls_session_set_premaster() is used (under openconnect),
it is possible that gnutls_session_get_desc will print a string like
this: "(DTLS1.2)-(ECDHE-(null))-(AES-256-GCM)"

With this change we ensure that we do not print null values.

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>

3 files changed, 325 insertions, 5 deletions

diff --git a/lib/session.c b/lib/session.c
index 68d1cebe5c..6deda99c07 100644
--- a/lib/session.c
+++ b/lib/session.c
@@ -413,16 +413,16 @@ char *gnutls_session_get_desc(gnutls_session_t session)
 			return NULL;
 		}
 
-		if (kx == GNUTLS_KX_ECDHE_ECDSA || kx == GNUTLS_KX_ECDHE_RSA || 
-		    kx == GNUTLS_KX_ECDHE_PSK) {
+		if ((kx == GNUTLS_KX_ECDHE_ECDSA || kx == GNUTLS_KX_ECDHE_RSA ||
+		    kx == GNUTLS_KX_ECDHE_PSK) && group_name) {
 			if (sign_str)
 				snprintf(kx_name, sizeof(kx_name), "(ECDHE-%s)-(%s)",
 					 group_name, sign_str);
 			else
 				snprintf(kx_name, sizeof(kx_name), "(ECDHE-%s)",
 					 group_name);
-		} else if (kx == GNUTLS_KX_DHE_DSS || kx == GNUTLS_KX_DHE_RSA || 
-		    kx == GNUTLS_KX_DHE_PSK) {
+		} else if ((kx == GNUTLS_KX_DHE_DSS || kx == GNUTLS_KX_DHE_RSA ||
+		    kx == GNUTLS_KX_DHE_PSK) && group_name) {
 			if (sign_str)
 				snprintf(kx_name, sizeof(kx_name), "(DHE-%s)-(%s)", group_name, sign_str);
 			else
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 98623a20c8..61c5a537b2 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -161,7 +161,7 @@ ctests += mini-record-2 simple gnutls_hmac_fast set_pkcs12_cred cert certuniquei
 	 cert-status fips-mode-pthread rsa-psk global-init sec-params sign-verify-data \
 	 fips-test fips-override-test mini-global-load name-constraints x509-extensions \
 	 long-session-id mini-x509-callbacks-intr mini-dtls-lowmtu set_x509_key_file-late \
-	 crlverify mini-dtls-discard init_fds mini-record-failure \
+	 crlverify mini-dtls-discard init_fds mini-record-failure openconnect-dtls12 \
 	 tls12-rehandshake-cert-2 custom-urls set_x509_key_mem set_x509_key_file \
 	 tls12-rehandshake-cert-auto tls12-rehandshake-set-prio \
 	 mini-chain-unsorted x509-verify-with-crl mini-dtls-mtu privkey-verify-broken \
diff --git a/tests/openconnect-dtls12.c b/tests/openconnect-dtls12.c
new file mode 100644
index 0000000000..21d1b2a1fb
--- /dev/null
+++ b/tests/openconnect-dtls12.c
@@ -0,0 +1,320 @@
+/*
+ * Copyright (C) 2019 Nikos Mavrogiannopoulos
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * GnuTLS is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuTLS is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_WIN32)
+
+int main()
+{
+	exit(77);
+}
+
+#else
+
+#include <string.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <signal.h>
+#include <assert.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/dtls.h>
+
+#include "utils.h"
+
+static void server_log_func(int level, const char *str)
+{
+	fprintf(stderr, "server|<%d>| %s", level, str);
+}
+
+static void client_log_func(int level, const char *str)
+{
+	fprintf(stderr, "client|<%d>| %s", level, str);
+}
+
+/* A DTLS client handling DTLS 1.2 resumption under AnyConnect protocol which sets premaster secret.
+ */
+
+#define MAX_BUF 1024
+
+static ssize_t
+push(gnutls_transport_ptr_t tr, const void *data, size_t len)
+{
+	int fd = (long int) tr;
+
+	return send(fd, data, len, 0);
+}
+
+static gnutls_datum_t master =
+    { (void*)"\x44\x66\x44\xa9\xb6\x29\xed\x6e\xd6\x93\x15\xdb\xf0\x7d\x4b\x2e\x18\xb1\x9d\xed\xff\x6a\x86\x76\xc9\x0e\x16\xab\xc2\x10\xbb\x17\x99\x24\xb1\xd9\xb9\x95\xe7\xea\xea\xea\xea\xea\xff\xaa\xac", 48};
+static gnutls_datum_t sess_id =
+    { (void*)"\xd9\xb9\x95\xe7\xea", 5};
+
+static void client(int fd, const char *prio, int proto, int cipher, int kx, int mac, const char *exp_desc)
+{
+	int ret;
+	char buffer[MAX_BUF + 1];
+	char *desc;
+	gnutls_certificate_credentials_t xcred;
+	gnutls_session_t session;
+
+	global_init();
+
+	if (debug) {
+		gnutls_global_set_log_function(client_log_func);
+		gnutls_global_set_log_level(4711);
+	}
+
+	gnutls_certificate_allocate_credentials(&xcred);
+
+	gnutls_init(&session, GNUTLS_CLIENT | GNUTLS_DATAGRAM);
+	gnutls_dtls_set_mtu(session, 1500);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+
+	assert(gnutls_priority_set_direct(session,
+					  prio,
+					  NULL) >= 0);
+
+	ret = gnutls_session_set_premaster(session, GNUTLS_CLIENT,
+		proto, kx, cipher, mac,
+		GNUTLS_COMP_NULL, &master, &sess_id);
+	if (ret < 0) {
+		fail("client: gnutls_session_set_premaster failed: %s\n", gnutls_strerror(ret));
+		exit(1);
+	}
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred);
+
+	gnutls_transport_set_int(session, fd);
+	gnutls_transport_set_push_function(session, push);
+
+	/* Perform the TLS handshake
+	 */
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+	if (ret < 0) {
+		fail("client: Handshake failed\n");
+		gnutls_perror(ret);
+		exit(1);
+	} else {
+		if (debug)
+			success("client: Handshake was completed\n");
+	}
+
+	desc = gnutls_session_get_desc(session);
+	if (desc == NULL)
+		fail("client: gnutls_session_get_desc: NULL\n");
+
+	if (strcmp(desc, exp_desc) != 0)
+		fail("client: gnutls_session_get_desc: found null str: %s\n", desc);
+
+	success(" - connected with: %s\n", desc);
+	gnutls_free(desc);
+
+	if (debug)
+		success("client: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	do {
+		ret = gnutls_record_recv(session, buffer, sizeof(buffer)-1);
+	} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+	if (ret == 0) {
+		if (debug)
+			success
+			    ("client: Peer has closed the TLS connection\n");
+		goto end;
+	} else if (ret < 0) {
+		fail("client: Error: %s\n", gnutls_strerror(ret));
+		exit(1);
+	}
+
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+
+      end:
+
+	close(fd);
+
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(xcred);
+
+	gnutls_global_deinit();
+}
+
+
+static void server(int fd, const char *prio, int proto, int cipher, int kx, int mac)
+{
+	int ret;
+	gnutls_certificate_credentials_t xcred;
+	char buffer[MAX_BUF + 1];
+	gnutls_session_t session;
+
+	/* this must be called once in the program
+	 */
+	global_init();
+
+	if (debug) {
+		gnutls_global_set_log_function(server_log_func);
+		gnutls_global_set_log_level(4711);
+	}
+
+	gnutls_certificate_allocate_credentials(&xcred);
+
+	gnutls_init(&session, GNUTLS_SERVER | GNUTLS_DATAGRAM);
+	gnutls_handshake_set_timeout(session, 20 * 1000);
+	gnutls_dtls_set_mtu(session, 1500);
+
+	/* avoid calling all the priority functions, since the defaults
+	 * are adequate.
+	 */
+	assert(gnutls_priority_set_direct(session,
+					  prio,
+					  NULL) >= 0);
+
+	ret = gnutls_session_set_premaster(session, GNUTLS_SERVER,
+		proto, kx, cipher, mac,
+		GNUTLS_COMP_NULL, &master, &sess_id);
+	if (ret < 0) {
+		fail("server: gnutls_session_set_premaster failed: %s\n", gnutls_strerror(ret));
+		exit(1);
+	}
+
+	gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred);
+
+	gnutls_transport_set_int(session, fd);
+	gnutls_transport_set_push_function(session, push);
+
+	do {
+		ret = gnutls_handshake(session);
+	}
+	while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+	if (ret < 0) {
+		close(fd);
+		gnutls_deinit(session);
+		fail("server: Handshake has failed (%s)\n\n",
+		     gnutls_strerror(ret));
+	}
+	if (debug)
+		success("server: Handshake was completed\n");
+
+	if (debug)
+		success("server: TLS version is: %s\n",
+			gnutls_protocol_get_name
+			(gnutls_protocol_get_version(session)));
+
+	/* see the Getting peer's information example */
+	/* print_info(session); */
+
+	memset(buffer, 1, sizeof(buffer));
+	do {
+		ret = gnutls_record_send(session, buffer, sizeof(buffer)-1);
+	} while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED);
+
+	if (ret < 0) {
+		close(fd);
+		gnutls_deinit(session);
+		fail("server: data sending has failed (%s)\n\n",
+		     gnutls_strerror(ret));
+	}
+
+
+	/* do not wait for the peer to close the connection.
+	 */
+	gnutls_bye(session, GNUTLS_SHUT_WR);
+
+	close(fd);
+	gnutls_deinit(session);
+
+	gnutls_certificate_free_credentials(xcred);
+
+	gnutls_global_deinit();
+
+	if (debug)
+		success("server: finished\n");
+}
+
+static void run(const char *name, const char *prio, int proto, int cipher, int kx, int mac, const char *exp_desc)
+{
+	int fd[2];
+	int ret;
+	pid_t child;
+
+	success("Testing %s\n", name);
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
+	if (ret < 0) {
+		perror("socketpair");
+		exit(1);
+	}
+
+	child = fork();
+	if (child < 0) {
+		perror("fork");
+		fail("fork");
+		exit(1);
+	}
+
+	if (child) {
+		int status;
+		/* parent */
+
+		close(fd[1]);
+		server(fd[0], prio, proto, cipher, kx, mac);
+		wait(&status);
+		check_wait_status(status);
+		close(fd[0]);
+	} else {
+		close(fd[0]);
+		client(fd[1], prio, proto, cipher, kx, mac, exp_desc);
+		close(fd[1]);
+		exit(0);
+	}
+}
+
+void doit(void)
+{
+	signal(SIGPIPE, SIG_IGN);
+
+	run("dtls1.2-aes128-ecdhe", "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-128-GCM:+AEAD:+ECDHE-RSA:+SIGN-ALL:%COMPAT",
+	    GNUTLS_DTLS1_2, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_KX_ECDHE_RSA, GNUTLS_MAC_AEAD, "(DTLS1.2)-(ECDHE-RSA)-(AES-128-GCM)");
+	run("dtls1.2-aes256-ecdhe", "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-256-GCM:+AEAD:+ECDHE-RSA:+SIGN-ALL:%COMPAT",
+	    GNUTLS_DTLS1_2, GNUTLS_CIPHER_AES_256_GCM, GNUTLS_KX_ECDHE_RSA, GNUTLS_MAC_AEAD, "(DTLS1.2)-(ECDHE-RSA)-(AES-256-GCM)");
+	run("dtls1.2-aes128-rsa", "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-128-GCM:+AEAD:+RSA:+SIGN-ALL:%COMPAT",
+	    GNUTLS_DTLS1_2, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_KX_RSA, GNUTLS_MAC_AEAD, "(DTLS1.2)-(RSA)-(AES-128-GCM)");
+	run("dtls1.2-aes256-rsa", "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-256-GCM:+AEAD:+RSA:+SIGN-ALL:%COMPAT",
+	    GNUTLS_DTLS1_2, GNUTLS_CIPHER_AES_256_GCM, GNUTLS_KX_RSA, GNUTLS_MAC_AEAD, "(DTLS1.2)-(RSA)-(AES-256-GCM)");
+}
+
+#endif				/* _WIN32 */